Process of forming a food package



Aug. 19, 1952 w. B. KUNZ PROCESS OF FORMING A FOOD PACKAGE Filed Jan. 28, 1948 ZO F490].

WALTER B K UNZ 1 INVENTOR ATTORNEY Patented Aug. 19, 1952 f UNITED... STAT rnoonss oF FORMING A FOOD PACKAGE Walter B. Kunz, Fredericksburg, Va;, assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware 7 Application mat-y 28, 1948, Serial No. 4,884

Withthe advent of regenerated cellulose there.

wasjpr'ovided a new type of material which was excellent for laminating, wrapping and packaging. There have also been developed other types of sheet materials, namely, films of cellulose acetate and so-called moistureproof regenerated cellulose which is a film of regenerated cellulose having a moistureproof thermoplastic coating on the surface thereot.

.. For certain uses thelcoated regenerated cellulose is; preferable to the uncoated sheeting since it is possible to seal: the coatedsheeting by the applicationof heat and pressurewithor without, a solvent. Likewise, it has been possible toseal moistureproof regenerated-cellulose or cellulose acetate sheeting by applying tothe surface thereof one of the organic solvents inwhich the materials are soluble, thus forming an adhesive in situ laydissolving part of the surface material. How-" ever, it invariably. has been found that similar methods maynot be successfully applied to hydrophilic cellulosic materials such as uncoated regenerated cellulose, inasmuch as these hydrophilic materials are neither heat-scalable nor solublein common organic solvents; There have been several attempts to providefother methods forisealing hydrophilic cellulosic materials, but none 101? these other methods has proved very satisfactory. 'For'cxample, it has been proposed heretofore to use as 'an' adhesive'subst'ance, "a".

solution of viscose which is applied to the surface ofthe hydrophilic' cellulosic material and the cel- 4 Claims. (Cl. 99171) cellulose by means of an aqueoussolu'tio'n of zincchloride which-is applied to the surface. of the cel1ulose-sheet material, thus dissolving some. of the cellulose from the" surface-and rormm faa adhesive solution in situ. .IUnfortunatelyflthi sf method of sealing regenerated ceIlulOse'isliKe-f wise unsatisfactory since the action 'oftheichloride is relatively slow and sinceit. islto iic. In particular, the toxicity of zinclchloriderenders it undesirable forjuse in connection withi iza'odv products,,medicinals, and 'other' substances in lulose of theyiscose regenerated insitu. How

ever, this method of sealing 'cellulosic materials.

very slow inasmuch as '.the viscose solution must be coagulated, regenerated, desulfurized and washed after it is applied to the surface, so that this method cannot be used in high speed machineryl' In addition, hydrogen sulfide is given off; during .the regeneration of the viscose and thisftends, to contaminate any articles or materials' with' whichit comes into contact O bvious-, 1y, these disadvantages make'the method com-' packaging by automatic machinery.

pletely unsatisfactory for use in wrapping and to seal i l s 75 1 ter als uch 1 as, regenerated.

tended for human consumption. This invention has for its principal-objectto provide methods of sealing and joining hydrophilic sheet materials and to provide packages comprising food products insealed wrapper or containers of hydrophilic sheet material that overcome objections and disadvantages found in the prior art. f 'I 'f- Another object of the. invention'is toprovide improved methods for sealing and joining hydrophilic sheet materials.

A .further object of the invention is'to provide improved packages comprising food productsin sealed wrappers' or containersof nydro'p'mnc sheet material;

Otherobjects and advantages of the invn-f tion will be apparent irom the following descripk tion and accompanying drawingin which isshown a form of apparatus with which thez'invention ee we se may be practiced and forms embodying the invention.

Figure 1 is a sideelevation partly inset a form of apparatus with'whic'h the invention may be practiced.

Figure 2 is aplan view of the form of eck- Figure 5 is a sectional view of 'another'ior'rhfoi package embodying the invention.

This invention in general comprises-rapidly and securely sealing or joining together hydrophilic sheet material by means of an acidified solution ofta watersoluble partially polymerihed heat-hardening resin to form awrap peror con tainerfor a food product wrapped or enclosed in hydrophilic sheet 7 material i that is .so sealed or joined together.

The ..'sealing material whichjis' or gas.

composition of the food product is-applied to' a' Y x1e] nature that does not'promoteiorjfawr the deg-f product, or the sheet material may be formed in-" to the container or wrapper and sealed. orljoined together as it is being filled with the iqod rproduct. The sheet material either in the'form of a fiat sheet or tube can be sealed or joined when it 'is either wet or dry.

The following are examples of hydrophilic sheet material that is contemplated in this in,-

vention: regenerated cellulose, denitrated cellulose nitrate, alkalisoluble water-insoluble cellulosic. materials" 'suchas carboxy-alkylcellulose merit paper andwaxed paper. 7

j Thelsealing material that is used is an acidified aqueous 7 solution of a partially polymerized water-solubleheat-hardening resin the polymerizationpif'which resin is accelerated by the presence'ofan acid in aqueoussolutionr Such resins that are suitable include the aminoplast resins such as the urea-formaldehyde and melaminef q'r'maldehyde resins and other types of' resins such as ketone-formaldehyde resins and certain types of-phenolic resins, The solution is'acidi- Iiedby' any non-toxic acid, acidic, or acid forming, substance that will dissolve readily in water to give a resin solution the pH of which lies in the range of 4.5 to 5.5,; for example, lsuch organic acids as lactic acid, acetic acid, citric acid, and tartaric acid, 2certain inorganic-salts such-"as'-,'ammonium chloride, ammonium sulfate,

and inonobasic ammonium phosphate.

' Insealing or'joining the hydrophilic sheet material together, the aqueous resin solution is applied tothe portion of the sheet material that i's'to'be sealed or joined together and the material to which theaqueous resinsolution has been applied; is overlapped or superposed and subjected to heat and pressure sumcient to drive fi the water and to polymerize the resin'to the heat-hardenedstatei Heating to a temperature of-approximately 180 to 220 czisfound'sufficientin most cases. The acid in the solution serves as a'polymerizingcatalyst for the resin.

The following are examples of thepractice j of the-invention:

Acasing'was 'pr eparedfb'y shaping, a strip of hydrophilic regenerated cellulose into a tubular casing andsealing the edges of the stripjby means of an aqueous solution containing a water-soluble heat-hardening melamine formaldehyde-resin (sold under the trade-name Melmac '7; 2'73---'7*) and lactic acid in the ratio 69.3 to l.

The lactic acid served as a c'atalyst forthe polyo3."regenerated'cellulose, the edge qeethe and ea ed o p o l .03 C T e h'alt' itreatm nltlfw ils iifiicient to.

nmsi eu etne smreprodu e avatar-re istan seal.

p her 'xanthates, cellulose xantho-ether, cellulose thiourethans, cellulose xantho fatty acids, and specialtypes of paper such as par'ch '4 Example 2 A casing was prepared by shaping a strip of de-nitrated cellulose nitrate into a tubular casing and sealing the edges of the strip by means of a solution containing a water-soluble heat-hardening melamine-formaldehyde resin (sold under thetrade nameMelmacAZO) and lactic acid in the'ratio 13i'7."to .1- Aftertthe resin solution had been applied to the edges of the strip of regenerated cellulose, the edges were pressed together and heated to approximately 180 C. The casing was drawn from the forming plate and tested. Pressures as high as approximately four pounds per square inch .wer.e:required to burst casings that had been immersed in both hot and cold water.

Example 3 A casing was prepared by the procedure described in Example 2 above,rusing a hydrophilic regenerated cellulose 'strip and an aqueous solution containinga water-soluble heat-hardening melamine formaldehyde resin"(sold under the trade nameMelmac 470) and lactic acid in the ratio 13.7 to 1. The resin seal: was heated to approximately 180 C. Tests indicated that pressures as high as two pounds per square inch were required to burst casings that had beenimmersed in botliihot and cold water. The pH" of a mixtureof ml. of'distilled water and 6: grams or the sealed casing was 5.2

Example 4 J A casing was prepared by shaping a strip or de-nitrated nitrocellulose into a tubular-casing; and the edges of the strip were overlapped and; sealed with an aqueous solution containing- 67.95% melamine-formaldehyde resin (sold-under the trade name Melmac 4'70; 13-380) and} 4.93% lactic acid; The overlapping edgesofthe tube to'which the'sealingmaterial hadbeen ap plied were pres'sedwith-a roller and then "heated to atemperature of--C.- to remove-the water from theresin solution and pol-ymerize the resin to 'form a secure bondor seal that was waterproof;

Referring to Figures 1, '2, and 3fof the drawing in which is shown a form of apparatus with which this invention may be practiced, reference character H) indicates a nozzle having-a'-thread-' ed end ll adapted to screw onthe outlet-pipe- "2: of a "conventional sausage meat container 9 to; replace the nozzle conventionally used thereon. Since the meat in the container-9 is cus-' tomarily placed under hydraulic pressure, "the thereismounted' a bracket I'3 adapted tosupport' I0'11' of c n a m h dmnhil 'q' h e material I4. mou ted a u -fo er '5 which. nc r lesythe n zzle ands a ranged. o sh than sheet ma e al n o a ub n '5. aboutv he. 'nozzlq- Thane is also mounted on 'the nozzle II]v a. lisluid reser! voir 21; for an acidified aqueous; resin s lut on;

having a lid '1 and means'such as a wick ".111 for applying this-solution, to 'a'tfleast one of the. Over} lapping surfaces or theh'ydrophilic'sheet to forrn' a longitudinal seam 18,. .arcuateroller or' shoj I9, at d y el tri m ns o he Iikei supported on a forked spring 20. and is positioned. to ply h a andpressure q h am I "fl i afiee ira le olie hesheeti at i aliizisr i ap'osition that 'the'center'an'd "theedges 0f the O h i or h nozzle h e. s;

sheet are displaced anequal'distanceirom the longitudinal axis of the nozzle; ,Thi is done, according to the embodiment of the invention shown in Figures 1 and 2, by forming the nozzle with a'reverse curve atthe end adjacent to the meat container, and there is provided a guide roller 28 which is so positioned that its upper surface lies in the same plane with the axis of the free end of the nozzle l0. Thus,'when the roll of sheet material is passed over this ,roller, it is roughly at the same level asthe center of the nozzle and is suitably positioned for the formation of the tubing. It is to be understood that the nozzle may be reversed so that the roll I4 is positioned on the top side of: the nozzle while the resin solution reservoir is on the underside,

inwhichcase the seam is formed on the under side of the nozzle. Instead :of using a wick 11, an equivalent means suchas a'roller or disk which dips into the resin solution and thencontacts an edge of the sheet material may-be employed, and such alternativexmeans isvparticularly adapted when the nozzle is-reversed.

Figure 315 a cross-section of the nozzle shown in Figure l and taken along the line 33 thereof, in which is illustrated the nozzle l0, and the sheet material l6 surroundingthe nozzle and overlappin'g at the top toform the seam l8. There is also shown the heated roller or shoe I9 that presses the. overlapping edges or theseam [8 against the nozzle III.

In the operation of this invention, the sheet material I4 is passed over the guide roller 28 through the forming means I5 and shaped thereby into a continuous tubing I6 having overlapping edges to form a seam [8. Between the overlapping edges there is applied an acidified aqueous solution of the resin from the wick l1, and the edges are then pressed together by mean of the arcuate heated roller or shoe l9 bearing on the upper surface of the nozzle. After the seamed tubing I6 passes beyond the end of the nozzle [0,

the tubing is tied and then may be filled with sausage meat. The flow of th sausage meat is controlled by means of the valve 8 and, if desired, the stuffed casing is twisted at intervals to provide sausage links.

It is to be understood that the seam produced by the tube-forming means may be a single flat overlapping seam as shown in Figure 3, or there may be produced a casing having two flat longitudinal seams l8 and l8a as shown in Figure 4. In another embodiment, the edges of the sheet material may be brought together in abutting relation to form an upstanding seam 25 as shown in Figure 5. Such a seam is particularly advantageous when the casing is to be used for skinless frankfurter inasmuch as the upstanding fin 25 may be readily grasped by the operator or by mechanical means to facilitate stripping a casing from the cooked sausage. It has been found that in a tubing having an upstanding seam of the type shown in Figure 5, that the easing will tear along the base of the seam in a regular manner. Accordingly, it is possible with the sausage shown in Figure 5 to strip the casings by automatic machinery rather than by hand, which is not possible with the seamless frankfurter-size casings heretofore employed because they do not tear in any regular manner.

While reference has been made for purpose of description to the use of the invention in the preparation of sausages, it is to be understood productionof other stufied products of aplastic nature,;for example, ice cream, fats, scrapple, and other meat products, as well as butter,;-cheese, lard, shortening, and the like, and it is to bejur there understood that changes and variations may be madewithout departing from thespirit and scope ofthe invention as defined in the appended claims.

;I claim: v.

l. The method of forming afood p-ackage by simultaneously forming a container ,and ,stuiiing the container with edible material I comprisin moving hydrophilic cellulosic sheet material hat? ing edge. portions in a longitudinal direction, applying an aqueous solution of partially polymerized melamine-formaldehyde resin and. lactic acid having a pH of 4.5 to 5.5 to an edge portion. of the hydrophilic cellulosic sheet material while it is being moved in a longitudinal direction and the edge portions are being positioned in opposed relation, positioning the edge portions of the hydrophiliccellulosic sheet material in opposedrrelation with the applied resin solutionbetween the opposed edge portions, and subjecting the opposed edge portions of the hydrophilic cellulosic sheet material whileitist-being moved in a longitudinal direction to heat and pressure suflicientto advance the polymerization ofx'the melamine-formaldehyde resin to the heat-hardened state to join and seal together the edge portions; of the hydrophilic cellulosic sheet material While it is being moved in a longitudinal direction, and stuffing the container with edible material as the container is formed.

2. The method of forming a food package by simultaneously forming a container and stufiing the container with edible material comprising moving hydrophilic regenerated cellulose sheet material having edge portions in a, longitudinal direction, applying an aqueous solution of partially polymerized melamine-formaldehyde resin and lactic acid having a pH of 4.5 to 5.5 to an edge portion of the hydrophilic regenerated cellulose sheet material while it is being moved in a longitudinal direction and the edge portions are being positioned in opposed relation, positioning the edge portions of the hydrophilic regenerated cellulose sheet material in opposed relation with the applied resin solution between the opposed edge portions, and subjecting the opposed edge portions of the hydrophilic regenerated cellulose sheet material while it is being moved in, a longitudinal direction to heat and pressure suificient to advance the polymerization of the melamine-formaldehyde resin to the heat-hardened state to join and seal together the edge portions of the hydrophilic regenerated cellulose sheet material while it is being moved in a longitudinal direction, and stuffing the container with edible material as the container is formed.

3. The method of forming a food package by simultaneously forming a container and stuffing the container with edible material comprising moving hydrophilic cellulose ether sheet material having edge portions in a longitudinal direction, applying an aqueous solution of partially polymerized melamine-formaldehyde resin and lactic acid having a pH of 4.5 to 5.5 to an edge portion of the hydrophilic cellulose ether sheet material while it is being moved in a longitudinal direction and the edge portions are being positioned in opposed relation, positioning the edge portions of the hydrophilic cellulose ether sheet material in opposed relation with the applied resin solution between the opposed edge portions, and subjecting the oiiido'sed eiige portionsnfthehydrophilio rcellu lose efiher sheet material while it is :being moved inm longitudinal direction to heat and pressure stimcien t to "advance the polymerization of the melamine-formaldehyde resin to the heat-hardene'd'stazte =to join and seal togetherth'e-edge per tions of the'hydrophi-lic cellulose ether -sheet ma;- terial while it is being moved in a longitudinal direction, and stufiing the container With-edible material as the --contai-ner is formed.

4. The method "of -forming e. food paxikage by simiiltaneeusly forming aconta'iner and =sltuffing the container with edible material comprising moving hydrophilic denit-ra'ted nitrocellulose sheet material having edge portions in a, longitutiinal direction, applying an aqueous solution-of partially -pol-ymerized inelamriin'e-formailclehy6e resin and lactic acid having a. 10H of 45 4:0 5:25 to an eflgemQr-ti'on of the hydrophilic denitreted nitrocellulose sheet material While it is being moved in a, longitudinal direction and v the edge portionsare being' positioned in opposed relation, positioningthe :edge portions of the hydrophilic denitrated nitrocellulose-sheet material in oppose'd' relaltion'with the applied resin solution 'between the opposed edge portions, and subjecting :the oipposed-edgeiportionsiof the'hydrophilicdeniirated nitrocellulose sheet material while it vis beingmoved in ;-a, longitudinal direction to heat and pressuresuficient tora'dva'nce'the polymerization of theimaelamine-iformaldehyde resin -'-to the REFERENCES CIT-ED The-following references are-of recor'ci file of this patent: t

UNLTED STATES "PATENTS Number Name :Date

Jlg846g575 Weingand Feb. .1932 51,905l999 LEllis e .Apr, 25,1933 3,901,031 Landt May 514,, 19.85 2,060,906 'Snyder "Nov. 1.7, 193.6 2,108,022 .Salemme Eeb. 18, 19-38 I 2,197,357 Widmer Apro 6,19% 2,210,436 We-ingand 'Aug. 6, 1940 $2,318,121 Widmer Mary 4;, 19.43 2,346,417 (iomwell e1; 12,1. Apr. 11:1, .1944 2,350,861 Mgy (June 6,1944 384,462 Goodman :Sept.'1-1, 19.45 2,395,077 .Southwick .Feb. 19,. 11-946 2;423;428 izPollaird .J1i1y :1, :1 947 24311035 Goepfert Nov.&8,:-194?7 2,432,542 Pitz1. Dec. 16, 19.47 Schaefer Sent-16,9194!) the 

1. THE METHOD OF FORMING A FOOD PACKAGE BY SIMULTANEOUSLY FORMING A CONTAINER AND STUFFING THE CONTAINER WITH EDIBLE MATERIAL COMPRISING MOVING HYDROPHLIC CELLULOSIC SHEET MATERIAL HAVING EDGE PORTIONS IN LONGITUDINAL DIRECTION APPLYING AN AQUEOUS SOLUTION OF PARTIALLY POLYMERIZED MELAMINE-FORMALDEHYDE RESIN AND LACTIC ACID HAVING A PH OF 4.5 TO 5.5 TO AN EDGE PORTION OF THE HYDROPHILIC CELLULOSIC SHEET MATERIAL WHILE IT IS BEING MOVED IN A LONGITUDINAL DIRECTION AND THE EDGE PORTIONS ARE BEING POSITIONED IN OPPOSED RELATION, POSITIONING THE EDGE PORTIONS OF THE HYDROPHILIC CELLULOSIC SHEET MATERIAL IN OPPOSED RELATION WITH THE APPLIED RESIN SOLUTION BETWEEN THE OPPOSED EDGE PORTIONS, AND SUBJECTING THE OPPOSED EDGE PORTIONS OF THE HYDROPHILIC CELLULOSIC SHEET MATERIAL WHILE IT IS BEING MOVED IN A LONGITUDINAL DIRECTION TO HEAT AND PRESSURE SUFFICIENT TO ADVANCE THE POLYMERIZATION OF THE MELAMINE-FORMALDEHYDE RESIN TO THE HEAT-HARDENDED STATE TO JOIN AN SEAL TOGETHER THE EDGE PORTIONS OF THE HYDROPHILIC CELLULOSIC SHEET MATERIAL WHILE IT IS BEING MOVED IN A LONGITUDINAL DIRECTION, AND STUFFING THE CONTAINER WITH EDIBLE MATERIAL AS THE CONTAINER IS FORMED. 